Optical fiber routing mat

ABSTRACT

Aspects of the present invention include an optical fiber routing mat for routing optical fibers. The optical fiber routing mat includes a first layer of material and a second layer of material. A surface of the first layer of material is adhesively coupled to a surface of the second layer of material. The optical fiber routing mat includes one or more optical fibers disposed between the first layer of material and the second layer of material. The one or more optical fibers are bent to a radius at least large enough to prevent damage to the one or more optical fibers.

STATEMENT REGARDING FEDERALLY SPONSORED WORK

This invention was made with United States Government support undercontract number H98230-12-R-1048 entered with the following UnitedStates Governmental Agency: Department of Defense. The United Statesgovernment has certain rights to this invention.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of opticalcommunications, and more particularly to a structure for managing andorganizing optical fiber interconnections.

Optical fibers are becoming more commonly used for signal transmissionin communications and information handling applications. Optical fibersprovide a large increase in the signal transmission bandwidth of atransmission cable over a given distance when compared with thebandwidth provided by conventional wire transmission cables. Becauseoptical transmission cables do not experience frequency-dependentattenuation of signals to the extent that conventional wire transmissioncables do, a greater amount of signal data can be transmitted overcables or signaling channels of comparable length. In addition, signaltransmission through optical fibers provides improved density versustransmission through electrical wires, since, for a given bandwidth, thecross-sectional areas of optical fiber cables and connectors aresignificantly smaller than for comparable electrical cables. Connectorsare used for joining light-transmitting optical fiber cables totransmitter devices, receiver devices or to other cables. In informationhandling applications, such as computer systems having large informationstorage capabilities, optical fiber transmission cables are used toprovide connections between units of the computer system in order tomost efficiently transmit large amounts of information from unit tounit.

Optical fibers have the disadvantage of being more physically fragile insome respects than metallic copper wire. For example, there is a limiton the minimum bend radius to which an optical fiber may be bent orcurved before degradation in the light transmission through the fiberoccurs. The optical fiber begins to leak light from the core due to thebend in the optical fiber. This loss of light from the optical fiberthereby increases the attenuation of the optical signals within theoptical fiber. In addition, internal micromechanical stresses in theoptical fiber caused by the tight bending can also physically degradethe optical fiber by reducing the amount of mechanical stress theoptical fiber may endure prior to breaking. Therefore the handling androuting of optical fibers and cables requires extra precaution to ensurethat the optical fibers are reliable at initial installation and overtime.

SUMMARY

Aspects of the present invention include an optical fiber routing matfor routing optical fibers. The optical fiber routing mat includes afirst layer of material and a second layer of material. A surface of thefirst layer of material is adhesively coupled to a surface of the secondlayer of material. The optical fiber routing mat includes one or moreoptical fibers disposed between the first layer of material and thesecond layer of material. The one or more optical fibers are bent to aradius at least large enough to prevent damage to the one or moreoptical fibers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts an isometric view of an optical fiber routing mat, inaccordance with an embodiment of the present invention;

FIG. 1B depicts an exploded isometric view of the optical fiber routingmat, in accordance with an embodiment of the present invention;

FIG. 2A depicts an isometric view of a first example of an optical fiberrouting mat, in accordance with an embodiment of the present invention;

FIG. 2B depicts an isometric view of a second example of an opticalfiber routing mat, in accordance with an embodiment of the presentinvention;

FIG. 2C depicts an isometric view of a third example of an optical fiberrouting mat, in accordance with an embodiment of the present invention;

FIG. 2D depicts an isometric view of a fourth example of an opticalfiber routing mat, in accordance with an embodiment of the presentinvention;

FIG. 2E depicts an isometric view of a fifth example of an optical fiberrouting mat, in accordance with an embodiment of the present invention;

FIG. 3 depicts an exploded isometric view of multiple optical fiberrouting mats stacked under external connectors of a printed circuitboard assembly, in accordance with an embodiment of the presentinvention;

FIG. 4 depicts a front isometric view of several optical fiberconnectors exiting multiple stacked optical fiber routing mats, inaccordance with an embodiment of the present invention; and

FIG. 5 depicts a bottom-side isometric view of several optical fiberconnectors exiting multiple stacked optical fiber routing mats andconnecting to a printed circuit board, in accordance with an embodimentof the present invention.

DETAILED DESCRIPTION

Electronic devices, and specifically semiconductor chips, are becomingincreasingly dense and capable of supporting increasing bandwidth. It isestimated that high performance chips may soon require thousands ofsignal input/output (I/O) channels. While some percentage of the I/Oscan be implemented as electrical I/Os through printed circuit boards(PCB), the signal integrity limitations of electrical I/Os, due toresistance loss, emission, radiation, and crosstalk, indicate advantagesto implementing a significant percentage of signal I/Os with opticalsignals. At the scale of density required by high performance electricalpackages, optical fiber routing design is important. As opticaltransceivers are developed to support an increasing number of opticalfibers, and optical fiber connectors are designed to match the increaseddensity, the routing of optical fibers from connector to connector ischallenging.

Embodiments of the present invention recognize that management andorganization of a large quantity of optical fibers from a dense array ofoptical fiber connectors can be improved by providing a design for anoptical fiber routing mat that provides a planar distribution of opticalfibers with an adequate bend radius to prevent damage. Implementation ofembodiments of the invention may take a variety of forms, and exemplaryimplementation details are discussed subsequently with reference to theFigures.

Embodiments of the present invention will now be described in detailwith reference to the accompanying drawings. It is to be understood thatthe disclosed embodiments are merely illustrative of potentialembodiments of the present invention and may take various forms. Inaddition, each of the examples given in connection with the variousembodiments is intended to be illustrative, and not restrictive.Further, the Figures are not necessarily to scale, and elements andfeatures can have different dimensions than those depicted in theFigures. Therefore, specific structural and functional details disclosedherein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

References in the specification to “an exemplary embodiment,” “otherembodiments,” etc., indicate that the embodiment described may include aparticular feature, structure, or characteristic, but every embodimentmay not necessarily include the particular feature, structure, orcharacteristic. Moreover, such phrases are not necessarily referring tothe same embodiment. Further, when a particular feature, structure, orcharacteristic is described in connection with an embodiment, it issubmitted that it is within the knowledge of one skilled in the art toaffect such feature, structure, or characteristic in connection withother embodiments whether or not explicitly described.

FIGS. 1A and 1B provide an illustration of only one implementation anddo not imply any limitations with regard to the different embodimentswhich may be implemented. Many modifications to the depicted embodimentmay be made by those skilled in the art without departing from the scopeof the invention as recited by the claims.

FIG. 1A depicts an isometric view of optical fiber routing mat 100, inaccordance with an embodiment of the present invention. It should benoted that although optical fiber routing mat 100 is depicted as arectangle in FIG. 1A, as well as subsequent Figures, optical fiberrouting mat 100 may be any regular or irregular geometric shape. Opticalfiber routing mat 100 includes optical fibers 102. Optical fibers 102include optical fibers that emanate from optical fiber connectors 108,110, 112, and 114 and the optical fiber ribbons associated with theoptical fiber connectors. For clarity, in the depicted embodiment,optical fibers 102 includes two optical fibers as not all of the opticalfibers emanating from optical fiber connectors 108, 110, 112, and 114are shown. The optical fiber ribbons from optical fiber connectors 108,110, 112, and 114 are stacked on each other such that the optical fibersfrom each optical fiber ribbon exit the optical fiber ribbons in a layerfor each optical fiber ribbon and enter optical fiber routing mat 100 inproximity with each other in a single layer. The depicted embodimentincludes four optical fiber connectors. In other embodiments, at leastone and up to twelve optical fiber connectors may be routed throughoptical fiber routing mat 100. In an embodiment where each of twelveoptical fiber connectors routing through optical fiber routing mat 100includes 64 optical fibers (16 in each of four optical fiber ribbons), atotal of 768 optical fibers are routed through optical fiber routing mat100. In another embodiment, more than twelve optical fiber connectorsmay be routed through optical fiber routing mat 100. Optical fiberrouting mat 100 enables routing of optical fibers from a first opticalfiber connector to a second optical fiber connector in a planarstructure that includes a large enough bend radius to protect theoptical fibers from damage. The routing of optical fibers from oneoptical fiber connector to another enables high speed signal routing andinterconnection of one or more integrated circuit (IC) package siteswithin one PCB or across one or more additional PCBs.

FIG. 1B depicts an exploded isometric view of optical fiber routing mat100, in accordance with an embodiment of the present invention. In theFigure, optical fiber routing mat 100 is depicted comprising mat layer104 and mat layer 106. Optical fiber routing mat 100 is fabricated byplacing optical fibers 102, emanating from optical fiber connector 108,on a surface of mat layer 104. In one embodiment, optical fibers 102 areplaced via automated assembly equipment. Optical fibers 102 are coupledto mat layer 104. In one embodiment, optical fibers 102 are coupled tomat layer 104 by a pressure sensitive adhesive coupled with or appliedto a surface of mat layer 104. After optical fibers 102 are coupled withmat layer 104, a surface of mat layer 106 is coupled with the surface ofmat layer 104 which is coupled with optical fibers 102. In oneembodiment, mat layer 104 and mat layer 106 are fabricated of apolyimide material. In another embodiment, mat layer 104 and mat layer106 may be fabricated of a polyester film, for example, Mylar®. In afurther embodiment, mat layer 104 and mat layer 106 may be fabricated ofone of a plurality of materials known in the art that provide enoughstructure and stability to prevent damage to the optical fibers routedbetween them. In an embodiment, mat layer 106 may include a pressuresensitive adhesive on the side that couples to mat layer 104. In anotherembodiment, mat layer 106 may be a conformal coating dispensed overoptical fibers 102 and mat layer 104.

FIG. 2A depicts an isometric view of a first example of optical fiberrouting mat 200A, in accordance with an embodiment of the presentinvention. Optical fiber routing mat 200A includes four sections:section 202, section 204, section 206, and section 208. In the depictedembodiment, each section is coupled with two optical fiber connectors.For example, section 202 is coupled with optical fiber connectors 210and 212, section 204 is coupled with optical fiber connectors 214 and216, section 206 is coupled with optical fiber connectors 218 and 220,and section 208 is coupled with optical fiber connectors 222 and 224. Inanother embodiment, one optical fiber connector is coupled with eachsection. In a further embodiment, more than two optical fiber connectorsare coupled with each section. In the depicted embodiment, the foursections of optical fiber routing mat 200A are not coupled with eachother. In the embodiment, each of the four sections includes opticalfibers routed from a single column in a PCB with four columns. Becausethe four sections are not coupled with each other, optical fibers routedwithin a section, for example, section 202, route signals fromintegrated circuit (IC) packages within the column to which section 202is associated, for example, from optical fiber connector 210 to opticalfiber connector 212.

FIG. 2B depicts an isometric view of a second example of optical fiberrouting mat 200B in accordance with an embodiment of the presentinvention. Optical fiber routing mat 200B includes four sections:section 202, section 204, section 206, and section 208. In the depictedembodiment, each section is coupled with two optical fiber connectors.In another embodiment, one optical fiber connector is coupled with eachsection. In a further embodiment, more than two optical fiber connectorsare coupled with each section. In the depicted embodiment, two of thefour sections of optical fiber routing mat 200B are coupled with eachother. For example, section 202 is coupled with section 204 via bridge226. In another example, section 206 is coupled with section 208 viabridge 228. Bridge 226 and bridge 228 are extensions of the two layersof material from which optical fiber routing mat 200B is fabricated, asdiscussed with respect to FIG. 1B. In one embodiment, bridge 226 andbridge 228 are narrow with respect to the width of a full section, butwide enough to accommodate one or more optical fibers. Optical fiberswithin optical fiber routing mat 200B can be routed through bridge 226and bridge 228 to enable an electronic coupling of section 202 tosection 204 and of section 206 to section 208. In the embodiment, eachof the four sections includes optical fibers routed from a single columnin a PCB with four columns. Because of the coupling between sections,optical fibers routed within a section, for example, section 202, canroute signals from IC packages within the column to which section 202 isassociated, for example, from optical fiber connector 210 to opticalfiber connector 212, as well as routing signals to and from IC packagesin a neighboring column i.e., the column to which section 204 isassociated.

FIG. 2C depicts an isometric view of a third example of optical fiberrouting mat 200C in accordance with an embodiment of the presentinvention. Optical fiber routing mat 200C includes four sections:section 202, section 204, section 206, and section 208. In the depictedembodiment, each section is coupled with two optical fiber connectors.In another embodiment, one optical fiber connector is coupled with eachsection. In a further embodiment, more than two optical fiber connectorsare coupled with each section. In the depicted embodiment, two of thefour sections of optical fiber routing mat 200C are coupled with eachother. For example, section 202 is coupled with section 206 via bridge226. In another example, section 204 is coupled with section 208 viabridge 228. Bridge 226 and bridge 228 are extensions of the two layersof material from which optical fiber routing mat 200C is fabricated, asdiscussed with respect to FIG. 1B. In one embodiment, bridge 226 andbridge 228 are narrow with respect to the width of a full section, butwide enough to accommodate one or more optical fibers. Optical fiberswithin optical fiber routing mat 200C can be routed through bridge 226and bridge 228 to enable an electronic coupling of section 202 tosection 206 and of section 204 to section 208. In the embodiment, eachof the four sections includes optical fibers routed from a single columnin a PCB with four columns. Because of the coupling between sections,optical fibers routed within a section, for example, section 202, canroute signals from IC packages within the column to which section 202 isassociated, for example, from optical fiber connector 210 to opticalfiber connector 212, as well as routing signals to and from IC packagesone column removed from section 202, i.e., the column to which section206 is associated.

FIG. 2D depicts an isometric view of a fourth example of optical fiberrouting mat 200D in accordance with an embodiment of the presentinvention. Optical fiber routing mat 200D includes four sections:section 202, section 204, section 206, and section 208. In the depictedembodiment, each section is coupled with two optical fiber connectors.In another embodiment, one optical fiber connector is coupled with eachsection. In a further embodiment, more than two optical fiber connectorsare coupled with each section. In the depicted embodiment, two of thefour sections of optical fiber routing mat 200D are coupled with eachother. For example, section 202 is coupled with section 208 via bridge226. In another example, section 204 is coupled with section 206 viabridge 228 (not shown). Bridge 226 and bridge 228 are extensions of thetwo layers of material from which optical fiber routing mat 200D isfabricated, as discussed with respect to FIG. 1B. In one embodiment,bridge 226 and bridge 228 are narrow with respect to the width of a fullsection, but wide enough to accommodate one or more optical fibers.Optical fibers within optical fiber routing mat 200D can be routedthrough bridge 226 and bridge 228 to enable an electronic coupling ofsection 202 to section 208 and of section 204 to section 206. In theembodiment, each of the four sections includes optical fibers routedfrom a single column in a PCB with four columns. Because of the couplingbetween sections, optical fibers routed within a section, for example,section 202, can route signals from IC packages within the column towhich section 202 is associated, for example, from optical fiberconnector 210 to optical fiber connector 212, as well as routing signalsto and from IC packages two columns removed from section 202, i.e., thecolumn to which section 208 is associated. In addition, optical fibersrouted within a section, for example, section 204, can route signalsfrom IC packages within the column to which section 204 is associated,for example, from optical fiber connector 214 to optical fiber connector216, as well as routing signals to and from IC packages in a columnsneighboring section 204, i.e., the column to which section 206 isassociated.

FIG. 2E depicts an isometric view of a fifth example of optical fiberrouting mat 200E in accordance with an embodiment of the presentinvention. Optical fiber routing mat 200E includes one section, i.e.,section 202. In the depicted embodiment, section 202 is coupled witheight optical fiber connectors, i.e., optical fiber connectors 210through 224. In another embodiment, section 202 may be coupled with lessthan eight or more than eight optical fiber connectors. Also coupledwith optical fiber routing mat 200E are external optical connectors 230.External optical connectors 230 are present to route optical signalsfrom four columns of a PCB with which optical fiber connectors 210through 224 are associated to other computing devices in informationtechnology (IT) equipment with which optical fiber routing mat 200E isassociated.

As may be evident to one skilled in the art, the embodiments depicted inFIGS. 2A through 2E may be combined into embodiments that contain two ormore of the depicted embodiments. In one embodiment that combines allfive depicted embodiments in a unified structure, optical fiberconnectors in each of sections 202, 204, 206, and 208 may haveconnectivity to optical fiber connectors in all of the sections 202,204, 206, and 208, across the different layers, as well as with externaloptical connectors 230. Such a structure represents an “all-to-all”topology which may be useful in certain aspects of IT equipment design.

FIG. 3 depicts an exploded isometric view of multiple optical fiberrouting mats stacked under external connectors of a printed circuitboard assembly, in accordance with an embodiment of the presentinvention. The embodiment depicted in FIG. 3 includes one of each of theexamples discussed and depicted with respect to FIGS. 2A through 2E. Inanother embodiment, the stack of two or more optical fiber routing matsmay include two or more of one of the examples discussed and depictedwith respect to FIGS. 2A through 2E. In further embodiments, variouscombinations of the configurations exemplified in FIGS. 2A through 2Emay be utilized. The Figure illustrates an embodiment where stacking ofmultiple optical fiber routing mats in one application enablesconnections between all IC packages coupled to a four column PCB as wellas enabling connections from the IC packages coupled to the PCB toexternal IT equipment, as described with respect to FIGS. 2A through 2E.Because of the physical nature of the optical fiber routing mats, a highdensity of optical fibers is routed in a small space while the opticalfibers are protected from damage and bent to an acceptable radius. Inone embodiment, the various optical fiber routing mats are notphysically coupled with each other. In another embodiment, one or moreof the optical fiber routing mats may be physically coupled with one ormore other optical fiber routing mats. For example, one or more opticalfiber routing mats may be coupled via pressure sensitive adhesive placedbetween two optical fiber routing mats. In another example, one or moreoptical fiber routing mats may be coupled via a clamping mechanism.

FIG. 4 depicts a front isometric view of several optical fiberconnectors exiting multiple stacked optical fiber routing mats, inaccordance with an embodiment of the present invention. The Figureillustrates eight sets of six adjacent optical fiber connectors. Eachset of six optical fiber connectors includes optical fiber ribbons thatextend to an optical fiber routing mat in the stack, as depicted withrespect to FIG. 3. In the depicted embodiment, the optical fiberconnectors couple with eight IC packages, two in each of four columns,on a PCB (not shown). In addition, external optical fiber connectors areavailable for coupling the PCB with external IT equipment.

FIG. 5 depicts a bottom-side isometric view of several optical fiberconnectors exiting multiple stacked optical fiber routing mats andconnecting to a printed circuit board, in accordance with an embodimentof the present invention. In the depicted embodiment, optical fiberribbons exiting the optical fiber routing mats couple with a single rowof IC sites. In another embodiment, one or more additional IC sites onthe PCB may be populated, and optical fiber ribbons exiting the opticalfiber routing mats couple with one or more rows of IC sites.

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration, but are not intendedto be exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the invention.The terminology used herein was chosen to best explain the principles ofthe embodiment, the practical application or technical improvement overtechnologies found in the marketplace, or to enable others of ordinaryskill in the art to understand the embodiments disclosed herein.

What is claimed is:
 1. An optical fiber routing mat comprising: a firstlayer of material and a second layer of material, wherein a surface ofthe first layer of material is adhesively coupled to a surface of thesecond layer of material, wherein the first layer of material and thesecond layer of material are each a polyester film; and one or moreoptical fibers disposed between the first layer of material and thesecond layer of material, wherein the one or more optical fibers arebent to a radius at least large enough to prevent damage to the one ormore optical fibers, wherein the one or more optical fibers emanate fromone or more optical fiber ribbons coupled with one or more optical fiberconnectors, and wherein the optical fiber routing mat is coupled with aplurality of external optical connectors.
 2. The optical fiber routingmat of claim 1, further comprising: two or more sections of the opticalfiber routing mat coupled by an extension of each of the first layer ofmaterial and the second layer of material; and one or more opticalfibers routed through the extension.
 3. The optical fiber routing mat ofclaim 2, wherein the coupled two or more sections of the optical fiberrouting mat are not adjacent to each other.
 4. The optical fiber routingmat of claim 2, wherein the extension is narrow with respect to a widthof a full section, and wide enough to accommodate one or more opticalfibers.
 5. The optical fiber routing mat of claim 1, further comprisinga pressure sensitive adhesive applied to the surface of the second layerof material, wherein the one or more optical fibers are adhesivelycoupled to the surface of the second layer of material via the pressuresensitive adhesive.
 6. The optical fiber routing mat of claim 1, whereinthe first layer of material and the second layer of material are each apolyimide material.
 7. The optical fiber routing mat of claim 1, whereinthe first layer of material is a conformal coating dispensed over theone or more optical fibers and the surface of the second layer ofmaterial.
 8. The optical fiber routing mat of claim 1, wherein the oneor more optical fiber connectors are coupled with one or more integratedcircuit packages on a printed circuit board.